Motor vehicles are equipped with a windshield wiper device for cleaning or wiping a surface of a windshield. The windshield wiper device includes a wiper blade, a wiper arm and a wiper motor oscillating the wiper arm. The wiper blade is placed on the surface of the windshield and is separably coupled to the distal end of the wiper arm. The wiper blade wipes the surface of the windshield while sliding thereon through oscillation motions of the wiper arm.
The wiper blade includes a wiper rubber and a lever assembly. The wiper rubber contacts the windshield surface. The lever assembly holds and supports the wiper rubber along its longitudinal direction. The lever assembly includes a main lever and a plurality of yoke levers linked to the main lever. The main lever is connected to the wiper arm. The yoke lever is linked to the main lever or another yoke lever at its middle. The main lever and the yoke lever are hinge-jointed by means of a pin or rivet.
When a motor vehicle runs, wind or air stream impinging against the windshield applies a force to the wiper blade along the longitudinal direction of the wiper blade. The wiper blade generally stands upright on the surface of the inclined windshield. Thus, the force applied by the wind or air stream acts to lift the wiper blade from the surface of the windshield. The faster the motor vehicle runs, the stronger such a lift force becomes. This weakens the contact between the wiper rubber and the windshield surface, thereby deteriorating wiping performance.
To address the deterioration in wiping performance caused by the lift of a wiper blade, it is known in the art to attach a spoiler to the wiper blade. The spoiler interacts with wind or air stream and thereby applies a force in a direction opposite to the lift of the wiper blade. By way of example, Korean Patent Application Publication No. 10-2001-0030699 proposes a wiper blade with a spoiler attached to a main lever. It is also known in the art to attach a cover to a wiper blade so as to cover a main lever and a yoke lever. By way of another example, Korean Patent Application Publication No. 10-2006-0051763 proposes a wiper blade with such a cover.